Currently, various grades of steel are produced by using ferroalloys as an alloying material. Generally, the ferroalloy is produced in a completely separate operation and often at a separate facility then the production of iron. The iron and ferroalloys are then brought together and combined to produce manganese steel.
The use of ferroalloys requires separate furnace operation and energy expenditures. The use of ferroalloys also leads to an inefficient recovery of manganese from the ores, or oxide materials, that are used to produce ferroalloys. Ferroalloy production occurs with high losses of manganese in the slag, or impurity containing material and as gaseous or fume loss.
The use of ferroalloys allows steel alloying to occur with an alloying element containing an increased manganese concentration compared to that of most manganese containing oxide materials. By using a ferroalloy converted from an oxide material there is less likelihood of non-metallic inclusions being present in the final product using current production methods.
Currently, high volume ferroalloys are produced by the reduction of manganese containing ores in a high temperature furnace. This produces a metallic manganese containing compound and a byproduct slag volume, or waste containing the impurities. If silicon use is kept to a minimum during the reduction the slag volume is roughly three times that of the metallic. In common SiMn and FeMn production the manganese content of the slag can range from ten to forty percent. Although the slag can be in essence reused to create a metallic it requires the use of additional compounds and energy use. The process of reusing slag is not as efficient as the initial reduction from a material and energy standpoint.
Current steelmaking can be broken down into several steps: iron refining, alloying, and conversion. Iron refining involves taking a raw iron source, usually iron ore- or scrap metal and heating in a furnace (blast furnace but could be oxygen enriched or electric reduction). This process results in a majority iron containing compound and a byproduct slag.
In alloying and conversion the necessary alloys are added to the iron source in a reduction furnace. This is the step at which currently ferroalloys are added to the steelmaking process. Once the conversion has occurred the final product is kept and the resulting slag, or impurities, is removed. During the conversion the impurities and desired compounds are reacted into compounds that will be left in the slag leaving the iron based alloy as the final product.
Accordingly, it is desirable to provide a method that combines the production of iron and manganese to result in a manganese steel.